The present invention relates to a method and a device for generating a character line of a uniform width through the process of character size conversion and, more particularly, to a uniform line generating method and device for generating high quality characters each having uniform in width vertical and horizontal lines through the process of reducing a size of an outline font composed of turning points.
Such a character-size reducing method has been proposed that a character is disassembled into a plurality of character parts, a sequence of turning points (with coordinates) composing one character part is multiplied by a reduction ratio and a resultant value is round off to an integer. This method, however, can not obtain high-quality characters because of lacking in consideration of line width of transformed characters. Each character of uniform line before its size conversion may have uneven line after conversion.
Japanese laid-open patent No. 1-303489 describes such a proposal that a character is converted in size under the condition that paired line-segments for determining a line width of a character is classified into a reference line-segment and a line-segment to be corrected and a space from a corresponding reference line-segment is taken as a reference width, and then coordinates of correctable line-segment after the character size conversion are determined by coordinates of the reference line-segment and a rounded value of the reference width after the character size conversion.
Since this method determines a reference line width of the converted character from a reference line width of the character before its size conversion, it may be supposed that when a line segment having a slightly different width is converted into a segment of a reduced size, the converted line may be of an uneven width due to a rounding error of the reference line width.
When a dot sequence of a line having a slight unevenness in its width is converted to be reduced in size, the unevenness of the line width may be produced mainly from a round-off error caused when coordinates of the converted dot sequence is rounded off to an integer.
When line widths of vertical and horizontal strokes contained in a character part are to be controlled, a reference line-segment for each directional stroke needs to be preset and a line width needs to be determined. Since the coordinate values of the reference line segments separately set for respective character parts are different from each other, the relative locations of the parts can not be maintained in the process of reducing the character size, resulting in sticking-out or separating of one character from another.